The invention relates to a screw assembly device for a screw driver for driving screws from a strip shaped screw magazine into a workpiece.
The German patent 24 44 457 discloses a screwing assembly for a screw driver, with screws, disposed in a strip-shaped magazine, can be driven into a workpiece. The screw assembly has a basic body, a guiding element, a carrier seat, a carriage, a transporting pawl and a carrier. The basic body is connected detachably with a housing of the screw assembly and the guiding element can be shifted relative to the housing of the screw assembly counter to the setting direction against the force of a spring element.
The guiding element is connected as a unit with the carrier seat, which extends perpendicularly to a setting direction of the screws and accommodates and guides the carriage. The carriage has a control element, which interacts with a control curve, disposed at the basic body. The carriage can be shifted against the force of a spring along the carrier seat in a direction opposite from the guiding element and perpendicularly to the setting direction. A pivotal transporting pawl, which is positively connected with the screw magazine, is disposed at the carriage. The carrier is fastened detachably at the carrier seat and has a transporting channel, which extends perpendicularly to the setting direction of the screws and accommodates as well as guides the strip-shaped screw magazine. The carrier is constructed essentially U-shaped and, at a free end region facing opposite to the setting direction, has two mutually opposite radial expansions, which extend over the whole length of the carrier and accommodate as well as guide the screw heads.
This known carrier is located at an end region end in the setting direction. Therefore, in the transporting channel, only screws can be accommodated, the length of which does not exceed the height of the transporting channel. The possibilities of using this known screwing device is therefore limited significantly, since screws, the length of which exceeds the height of the carrier, cannot be used. In addition, the removal of a strip-shaped screw magazine, which is inserted in the screw assembly, in a direction facing away from the guiding element, is associated with difficulties, since the transporting pawl, which is not accessible from the outside, interacts in the carriage of the screw assembly positively with the strip of the screw magazine.
It is an object of the invention to create a screw assembly for a screwing device, the carrier of which can be used firmly with the transport seat and with which screws can be processed, which are longer than the height of the guiding channel in the carrier, measured parallel to the setting direction. In addition, it is possible to eliminate the positive connection between the transporting pawl and the strip-shaped screw magazine rapidly and easily, so that it becomes possible to remove the screw magazine from the guiding channel of the carrier in a direction away from the guiding element.
The inventive screw assembly has the advantage that the connection between the carrier and the carrier seat can be made or released rapidly with simple manipulations.
Preferably the fastening pawl is disposed at the carrier and can be shifted, for example, against the force of a spring plate essentially parallel to the setting direction into a release position. Advisably, the stop is at an end region of the carrier seat, spaced from the guiding element. A fastening surface of the fastening pawl grips behind this stop, when the carrier is slipped on to the carrier seat end and the user releases the fastening pawl, so that the latter can be pressed with the help of the spring plate into a fastening position.
In the region of the guiding element, the inventive screw assembly has a guiding channel, which extends perpendicularly to the setting direction, for the screw magazine. So that an essentially coaxial alignment of the transporting channel, which is disposed in the carrier, can be attained with respect to the guiding channel in the guiding element, the carrier must be centered appropriately with respect to the carrier seat. Advisably, at least one centering lug of the carrier, which protrudes positively into a centering guide of the guiding element, serves for the centering of the carrier at the guiding element.
Preferably an additional centering of the carrier at the carrier seat is attained with a centering pin of the carrier, which extends in the direction of the guiding element and engages an appropriately constructed centering region of the carrier seat. This centering region is at an end region of the carrier seat, spaced from the guiding element, and has a cross section, which extends parallel to the setting direction as well as perpendicularly to the longitudinal extent of the carrier seat and corresponds essentially to the cross-section of the centering pin.
The carriage of the transporting device transports a strip-shaped, screw magazine, which can be inserted into the transporting channel of the carrier, in the direction of the guiding element. For each setting process, the screwing device is pressed against a workpiece. At the same time, the guiding element is shifted in the direction of the basic body and the control surface, disposed at the carriage, acts together with the control curve, disposed at the basic body of the screwing device. At the same time, the carriage is shifted in a direction, away from the guiding element, along the carrier seat into a transporting position. After the setting operation, the screw device and screw assembly are lifted from the workpiece. At the same time, the control surface releases the control element once again and the carriage is shifted with the help of a spring back into its starting position. This shifting is achieved advisably with a pre-tensioned spring, which acts over a stud, protruding over the centering pin in the direction of the guiding element, together with a stop surface of the carriage.
A transporting pawl, which can be pivoted from a transporting position into a release position when a screw magazine is inserted into the transporting channel, protrudes into the clear width of the transporting channel of the carrier, when a screw of the screw magazine, closest to the guiding element, is pushed past the transporting pawl. As soon as the screw has passed by the transporting pawl, the latter pivots back into its transporting position. The transporting pawl is shifted for a brief moment from the transporting position into a release position by the next screw, which is to be set, also when the carriage is shifted along the carrier seat in a direction away from the guiding element. An automatic pivoting back of the transporting pawl from a release position into a transporting position is advantageously achieved owing to the fact that a catch of the transporting pawl is disposed between the stud and the stop surface. Accordingly, the catch, and also the stop surface of the carriage, act together with the spring, which is disposed in the carrier. This spring is compressed whenever the carriage is shifted into a loading position and/or the transporting pawl is pivoted into a release position.
A strip-shaped screw magazine, guided in the transporting channel of the carrier and connected positively with the transporting pawl, can be removed from the carrier counter to the transporting direction only if the positive connection of the screw magazine with the carrier is undone. This positive connection can be undone quickly and easily by a user, if the transporting arm of the transporting pawl in a direction extending parallel to the setting direction and perpendicularly to the longitudinal extent of the carrier seat, advisably protrudes at least partly through a lateral slot in the carrier into the transporting channel of the carrier. The inventive transporting pawl can readily be taken hold of by the user and can be pivoted with respect to the carriage into the release position, in which the transporting arm of the transporting pawl, for example, no longer protrudes into the transporting channel.
When setting or screwing screws into a workpiece, high setting rates can be achieved only if the contacting path of the screw assembly is as small as possible. For this reason, it is advisable to supply the screws to the guiding element as close as possible to the surface of the workpiece. So that this becomes possible, preferably the transporting channel of the carrier is disposed counter to the setting direction in front of the carrier seat.
A multi-purpose usability of the screwing device is achieved owing to the fact that a strip-shaped screw magazine with screws of large length can be used in the transporting channel. For this purpose, the transporting channel advantageously is constructed open in the setting direction.
Particularly if long screws are to be used, the tips of the screws protrude from the carrier. So that these tips cannot scratch of the surface of the workpiece, the distance of the transporting channel from a plane, extending perpendicularly to the setting direction counter to the setting direction, increases as the distance from the guiding element increases. For example the transporting channel is constructed partly curved, with the curved section adjoining a section which extends perpendicularly to the setting direction and adjoins the guiding element directly.